This is a proposal for continuation of support for a research training program in Neuroepidemiology. To our knowledge, it is the oldest and one of the only NIH-funded Neuroepidemiology training programs in the United States. The goal of the program is to prepare neurologists and other research scientists for research careers in the epidemiology of neurologic disorders. Since its inception, the program has trained neurologists and neuroscientists who are now assistant professors, associate professors, professors or career research scientists at major academic institutions, the NIH, and elsewhere. The program, which has completed its 32nd year of funding, has capitalized upon the strengths of the Department of Neurology (College of Physicians and Surgeons), the Departments of Epidemiology and Biostatistics (Mailman School of Public Health), and the inter-disciplinary structure of the Gertrude H. Sergievsky Center, all at Columbia University Medical Center. The program provides stimulating training in a research environment for developing neuroscientists who wish to use epidemiologic methods to study diseases of the nervous system, and have as a career goal, a research or academic position. The structured, didactic training provided by the curriculum at the Mailman School of Public Health, combined with the opportunity to participate in and expand upon ongoing epidemiologic studies of neurologic disease conducted by program faculty, provide trainees with an optimal training for academic positions. Trainees will have the opportunity to work on large ongoing epidemiological studies utilizing multiple different study designs, including case-control and prospective cohort studies such as the Northern Manhattan Study, the Washington-Heights Inwood Study of Aging, and the Consortium on Risk for Early Onset Parkinson's Disease, and the Environmental Epidemiology of Essential Tremor Study. Our past trainees have successfully competed for independent funding from the NIH and other sources. We are requesting support for four MD/DO neurologists or appropriate postdoctoral neuroscientists (PhD or equivalent) each year for five years. All trainees will spend two years in the program, during which time sequenced didactic course work in epidemiology and biostatistics will be integrated with increasingly independent research activity. A degree (MS in Epidemiology from Mailman School of Public Health) is the recommended course for most trainees.